Wellesley is once again smack in the middle (as well as at the start and finish) of much of this weekend’s Pan-Mass Challenge, the annual bike-a-thon spearheaded by Wellesley’s own Billy Starr. Tonight’s opening ceremonies from Sturbridge will be televised live on NECN at 8pm, and cyclists will take off from Wellesley (at Babson College) and other locations tomorrow and Sunday, some riding 1 day and others 2 days. At 7 a.m. on Saturday, the riders will pass through Forest St and continue towards Needham on route to Bourne. At 7:30 a.m. on Sunday Aug. 3, riders will depart Wellesley through Forest St and continue towards Needham. Cyclists will return to Wellesley by Forest St to end at Babson College between 8 a.m. and 1:10 p.m. (So you might want to avoid driving in those areas at that time but find a way over there to cheer riders alongside the route). Routes range from 47 to 190 miles, and 5,500 riders will take part and hope to raise $34 million for cancer research. More than 150 Wellesley residents will be cycling and many others are volunteering. Also taking part will be a slew of Red Sox players’ wives, so don’t be surprised if a few of the Sox show up to cheer on their spouses. Feel free to to send along stories/photos for posting on this site to firstname.lastname@example.org.